#container {
    height: auto;
    width: 540px;
    background-color: white;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-evenly;
    align-content: space-evenly;
    margin: 0 auto;
}

#generate-sudoku {
    margin: auto;
    display: block;
    ;
}

#solve {
    margin: auto;
    display: block;
    ;
}

#container div {
    background-color: whitesmoke;
    height: 60px;
    width: 60px;
    box-sizing: border-box;
    font-family: sans-serif;
    text-align: center;
    vertical-align: middle;
    line-height: 60px;
    font-size: 30px;
    color: red;
}

#container div:hover {
    background-color: rgb(250, 250, 135);
}

.lsb {
    border-left: black 2px solid;
}

.bsb {
    border-bottom: black 2px solid;
}

.rsb {
    border-right: black 2px solid;
}

.tsb {
    border-top: black 2px solid;
}

.ldb {
    border-left: black 0.6px dashed;
}

.bdb {
    border-bottom: black 0.6px dashed;
}

.rdb {
    border-right: black 0.6px dashed;
}

.tdb {
    border-top: black 0.6px dashed;
}